Shape memory alloys/superelastic alloys, such as copper alloys, exhibit a remarkable shape memory effect and superelastic characteristics concomitantly to reverse transformation of the thermoelastic martensite transformation, and have excellent functions near the living environment temperature. Accordingly, these alloys have been put to practical use in various fields. Representative alloys of the shape memory alloys/superelastic alloys include TiNi alloys and Cu-based alloys. Copper-based shape memory alloys/superelastic alloys (hereinafter, copper-based alloys) have characteristics inferior to those of TiNi alloys in terms of repetition characteristics, corrosion resistance, and the like. On the other hand, since the cost is inexpensive, there has been a movement to extend the application range of copper-based alloys. However, although copper-based alloys are advantageous in terms of cost, those alloys are poor in cold workability and inferior in superelastic characteristics. For this reason, despite that a variety of studies are being conducted, it is the current situation that practicalization of copper-based alloys has not been necessarily sufficiently progressed.
Heretofore, various investigations have been conducted on copper-based alloys. For example, Cu—Al—Mn-based shape memory alloys having a recrystallized texture in which particular crystalline orientations, such as <101> and <100>, of a β single phase are aligned in the direction of cold work, such as rolling or wire-drawing, for example, having a β single phase structure with excellent cold workability, have been reported in Patent Literatures 1 to 4 described below.